JPH0448428A - Rotary erasing head device for magnetic recording and reproducing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a magnetic recording and reproducing device such as a video tape recorder that records and reproduces audio and video signals, and in particular, a rotary eraser for erasing video signals. The present invention relates to a rotary erasing gutter device for a magnetic recording/reproducing device equipped with a head.

[Conventional technology]

Conventionally, a video tape recorder (hereinafter referred to as a VTR) as a magnetic recording/reproducing device, for example, is equipped with a rotating recording/reproducing head provided on a rotating drum for recording and reproducing video signals, and a full-width erasing head that is not rotated. There is something. In such a VTR, when recording a new video signal on a track on which a video signal has already been recorded, the full-width erase head erases the already recorded signal before recording using the rotary recording/playback head. A new video signal is recorded using a rotating recording/reproducing head. However, in such a configuration, due to the difference in scanning trajectory between the rotary recording/playback head and the full-width erase head, there are parts that are not erased by the full-width erase head, and these parts are overwritten with a new video signal on the previous video signal. This results in a situation where the To solve this problem, for example, in broadcasting helical VTRs and commercial U-standard VTRs, a rotary erasing gutter is provided on the rotating drum in advance of the rotating recording/reproducing head. The head completely erases the already recorded video signal before recording a new video signal.

As a conventional VTR of this type, a two-hendo type VTR equipped with a rotary erasing head is known. In this VTR, as shown in FIG. 6, two rotary recording/reproducing heads 12a and 12b are arranged on the outer periphery of a rotary drum 11 at an interval of 180 degrees. The rotary erasing head 13 is disposed at an intermediate position between the two rotary recording/reproducing throats 12a and 12b on the rotational direction N side of the rotary recording/reproducing head 12a.

Assume that the above-mentioned VTR is capable of recording and reproducing at tape running speeds of 1x speed and 1/3x speed. Here, if the pitch of the video track 15 scanned by the rotary recording/reproducing heads 12a and 12b at 1x tape running speed is P', then the pitch of the video track 15 at 1/3x tape running speed is P'. '/3. Also, for rotation erasing, the track width of the gutter 13 is 2P, which is twice the pitch P' of the video track 15 when the tape running speed is 1x.
′.

In the above case, the erasing operation of the video track 15 by the rotary erasing head 13 when the tape running speed is 1x speed and 1/3x speed will be shown below. Note that J and K shown in FIGS. 7 and 8 are the scanning loci of the gutter 13 for rotation erasure at 1x speed and 1/3x speed, and L is the trajectory of the chi 11
4 is the running direction, and M is the scanning direction of the rotary erasing head 13. Further, a marked on the video track 15 indicates the video track 15 scanned by the rotary recording/reproducing head 12a, and b
indicates the video track 15 scanned by the rotary recording/reproducing head 12b.

As shown in FIG. 7, the rotating erasing head 13
By scanning the top once, the rotary eraser 13 erases two video tracks 15. Also, 1
/ At 3x speed, as shown in Figure 8, go to rotation erase nozzle 1.
3 erases six tracks of the video track 15.

For this reason, as shown in FIGS. 9 and 10, when recording ends (T), the gutter 13 goes to rotation erasing and finally erases (
After performing Q), the control means controls the two rotary recording/reproducing heads 12a-12b to move over the tape 14 once at 1x speed in order to avoid leaving unrecorded track areas when overwriting is performed, for example, during editing. Operation control is performed to scan and record (R) one by one.

Further, the control means controls the operation so that at 1/3 times the speed, the two rotary recording/reproducing heads 12a and 12b scan the tape 14 three times each to record (R).

[Problem to be solved by the invention]

However, in the conventional configuration described above, the control means must individually control the timing of the recording operation by the rotary recording/reproducing heads 12a and 12b after the erasing operation by the rotary erasing head 13, depending on the tape running speed. Therefore, a control circuit is required that performs complicated timing control of multiple recording operations that vary depending on the tape running speed.

Therefore, the present invention provides a rotary erasing head for a magnetic recording/reproducing device in which the control means performs the same timing control of the recording operation at all tape running speeds, and the control circuit that performs the timing control of the recording operation can be unified. The purpose is to provide equipment.

[Means for Solving the Problems] In order to solve the above problems, a magnetic recording and reproducing device according to the present invention is provided with a rotating drum that is provided on a rotating drum and that records and plays video signals by scanning a magnetic tape. It has a recording/reproducing head and a rotating erasing head which is installed on a rotating drum and scans the magnetic tape to erase the video signal.The tape running speed can be set to multiple levels, and the rotating recording/reproducing head erases the magnetic tape. In a rotary erasing head device of a magnetic recording/reproducing apparatus, the pitch of video tracks formed at different speeds varies according to each tape running speed, and the following measures are taken.

That is, the rotating erasing heads are individually provided according to each tape running speed, and each rotating erasing head has a video tape formed by the track width of each rotating erasing head and the tape running speed corresponding to the rotational erasing groove. The recording head is formed to have a constant ratio to the track pitch, and is provided with control means for switching each rotary erasing head in accordance with the selected tape running speed.

[For production]

According to the above configuration, a dedicated rotary erasing head is selected depending on the tape running speed so that the same video track is erased when the rotating erasing head scans the tape once even if the tape running speed is different. It is equipped. This rotary erasing head is switched by the control means according to the selected tape running speed.

Therefore, at all tape running speeds, the control means
The timing control of the recording operation by the rotary recording/reproducing head after the erasing operation by the rotary erasing head can be performed by the same control circuit.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

The magnetic recording and reproducing apparatus according to the present invention is a two-head video tape recorder (hereinafter referred to as VTR). This VTR is capable of recording and reproducing at tape running speeds of 1x speed and 1/3x speed. As shown in FIG. 1, this VTR has two rotary recording/reproducing heads 2a and 2b for recording video signals on a magnetic tape 4 and detecting the video signals. Also, this VTR has 1
It has a rotating erasing head 3a for double speed and a rotating erasing head 3b for 1/3x speed. This rotating erasing head 3a.
3b erases the already recorded video signal prior to recording of the video signal by the rotary recording/reproducing heads 2a and 2b.

The above two rotary recording/reproducing heads 2a and 2b are provided on the outer peripheral surface of the rotary drum 1 at an interval of 180°, and the two rotary erasing heads 3a and 3b are rotary recording and reproducing heads. Rotating recording/reproducing head 2a on the rotational direction E side of 2a
- Provided adjacent to each other at the intermediate position of 2b. These rotary recording/reproducing//dots 2a, 2b and rotary erasing heads 3a, 3b are driven by a rotary drum driving means 6 shown in FIG. 5 to scan the magnetic tape 4. The magnetic tape 4 is driven by a tape drive means 7 and runs while slidingly contacting the rotary recording/reproducing heads 2a, 2b and the rotary erasing heads 3a, 3b.

The rotating erasing heads 3a and 3b described above are the rotating erasing heads 3a and 3b.
The track widths of a and 3b are the same as those of the rotating erasing heads 3a and 3.
The pinch is twice as large as the pinch of the video track 5 formed by the tape running speed corresponding to b. That is, if the pitch of the video track 5 at the tape running speed of 1x speed is P, then the rotary erasing head 3a at the 1x speed is as shown in FIG.
The track width is 2P.

Furthermore, as shown in FIG. 3, the rotary erasing head 3b at 1/3x speed is such that the pitch of the video track 5 at this time is P/
3, so the trunk width of the rotating erasing head 3b is 2P.
/3.

In the above case, the erasing operation of the video track 5 by the rotary erasing heads 3a and 3b when the tape running speed is 1x speed and 1/3x speed is shown in FIGS. 2 and 3. Note that A and B shown in Figures 2 and 3 are for 1x speed and 1/1 speed.
These are the scanning trajectories of the rotating erasing heads 3a and 3b at triple speed, where C is the running direction of the tape 4 and D is the scanning direction of the rotating erasing heads 3a and 3b. Further, a marked on the video track 5 indicates the video track 5 scanned by the rotary recording/reproducing head 2a, and b indicates the video track 5 scanned by the rotary recording/reproducing head 2b.

The VTR also includes a microcomputer (hereinafter referred to as microcomputer) 8 as a control means shown in FIG. The microcomputer 8 controls the tape drive means 7 and the tape running speed based on input from an input key 9 provided on the outside of the main body of the VTR. At this time,
The microcomputer 8 controls the rotary drum driving means 6, and controls the relative relationship between the speeds of the rotary recording/reproducing heads 2a and 2b and the tape running speed. Also, at this time, the microcomputer 8 switches the rotation erasing ports 3a and 3b according to the selected tape running speed. The microcomputer 8 then rotates the erasing head 3a.
Or the rotating recording/reproducing head 2a after the erasing operation by 3b.
- Controls the timing of the recording operation by 2b.

In the above configuration, when the tape running speed of 1x speed is selected by operating the input key 9, the microcomputer 8 selects the rotary erasing head 3a and performs switching with the rotary erasing head 3b. . And the fourth
As shown in the figure, after the rotating erasing head 3a performs erasing (F), the microcomputer is configured so that the two rotating recording/reproducing heads 2a and 2b scan the tape 4 once and record (G). Operation control is performed by 8. The above operation control is continued until the end of recording (H).

Further, when the tape running speed of 1/3 times speed is selected by operating the input key 9, the microcomputer 8 selects the rotary erasing head 3b and switches between it and the rotary erasing head 3a.

The operation control by the microcomputer 8 is the same as that at the 1x speed shown in FIG.
The control means performs recording (G) by scanning the tape 4 once at a time, and this operation control is continued until recording is completed (H).

In this way, the timing control of the recording operation by the rotary recording/reproducing heads 2a and 2b after the erasing operation by the rotary erasing head 3a or 3b performed by the microcomputer 8 is the same regardless of the tape running speed.

In this embodiment, the VTR is 1x speed and 1/3 speed.
This setting allows recording and reproduction at a tape running speed that is double the tape running speed, but it is possible to set two or more tape running speeds. For example, a VTR may be set to be capable of recording and reproducing at three tape running speeds: 1x speed, 1/2x speed, and 1/3x speed.

In this case, three rotating erasing heads are provided for each tape running speed.

〔Effect of the invention〕

As described above, in the magnetic recording and reproducing apparatus according to the present invention, the rotating erasing heads are individually provided according to each tape running speed, and each rotating erasing head has a trunk width of each rotating erasing head and a rotation erasing head of the rotating erasing head. The video track is formed such that the ratio of the pinch to the video track formed by the tape running speed corresponding to the tape running speed is constant, and the structure includes a control means for switching each rotary erasing head in accordance with the selected tape running speed. It is.

Thereby, the timing control of the recording operation by the rotary recording/reproducing head after the erasing operation by the rotating erasing head performed by the control means is the same at all tape running speeds. Therefore, it is possible to unify the control circuit that controls the timing of the recording operation and to reduce manufacturing costs.

[Brief explanation of the drawing]

1 to 5 show one embodiment of the present invention. FIG. 1 is a schematic diagram showing the arrangement of a rotary recording/reproducing head and a rotary erasing head provided on a rotary drum. FIG. 2 is a schematic diagram showing the erasing operation of a video track by the rotary erasing head at a tape running speed of 1× speed. FIG. 3 is a schematic diagram showing the erasing operation of the video tracker by the rotary erasing head at a tape running speed of 1/3 times the speed. FIG. 4 is a timing chart showing the erasing operation of the rotary erasing head and the recording operation of the rotary recording/reproducing head at the end of recording. FIG. 5 is a block diagram showing the configuration of the main parts of the magnetic recording and reproducing apparatus. 6 to 10 show conventional examples. FIG. 6 is a schematic diagram showing the arrangement of a rotary recording/reproducing head and a rotary erasing head provided on a rotary drum. FIG. 7 is a schematic diagram showing the erasing operation of a video track by the rotary erasing head at a tape running speed of 1× speed. FIG. 8 is a schematic diagram showing the video track erasing operation by the rotary erasing head at 1/3 tape running speed. FIG. 9 is a timing chart showing the erasing operation of the rotary erasing head and the recording operation of the rotary recording/reproducing head at the end of recording at a tape running speed of 1.times. FIG. 10 is a timing chart showing the erasing operation of the rotary erasing head and the recording operation of the rotary recording/reproducing head at the end of recording at a tape running speed of 1/3 times the speed. ■ is a rotating drum, 2a and 2b are rotating recording and reproducing heads, 3
Reference numerals a and 3b denote rotary erasing heads, 4 a magnetic tape, 5 a video track, and 8 a microcomputer (control means).

Claims (1)

[Claims] 1. A rotary recording/reproducing head provided on a rotating drum and recording and reproducing video signals by scanning a magnetic tape;
A rotating erasing head that is installed on a rotating drum and scans the magnetic tape to erase the video signal, the tape running speed can be set to a plurality of values, and the video is formed on the magnetic tape by the rotating recording/reproducing head. In a rotary erasing head device of a magnetic recording/reproducing device in which the track pitch differs depending on each tape running speed, the above-mentioned rotating erasing heads are individually provided according to each tape running speed, and each rotating erasing head is While the ratio of the track width of the head to the pitch of the video track formed by the tape running speed corresponding to that rotating erasing head is constant, each rotational erasing is done according to the selected tape running speed. 1. A rotary erasing head device for a magnetic recording/reproducing device, comprising a control means for switching heads.